Update on February 5:A Facebook rep on its security team tells us that, to the company’s knowledge, nothing has changed on its end and isn’t sure why the app isn’t working, indicating Facebook did not intentionally block Crypter from the network. The story has been updated accordingly.

Crypter, a Chrome and Firefox extension that encrypts Facebook messages and prevents them from being snooped on, was rendered unusable after a Facebook Messenger update. Crypter claims that Facebook “depreciated” the service from working with Facebook Messenger (h/t The Next Web). Facebook, however, tells us that nothing has changed on their end, and says the issue lies with Crypter’s code.

“Facebook had no contact with us,” Maximilian Mitchell, Crypter’s creator, told Digital Trends. “It was working perfectly yesterday morning until TechCrunch published an article about us that afternoon. Around a similar time, Facebook updated Messenger, rendering Crypter disabled beyond repair. I spent most of last night looking for workarounds but it looks like, as we feared, Facebook are monitoring each key press before the user has even sent the message.”

While Facebook says it only learned about the app after TechCrunch’s article was posted, “the code for the Messenger update would have been written so long ago as to not affect any particular app,” a Facebook rep tells us. That means Facebook wasn’t aware of Crypter while it was developing its latest update. Adding that its engineers investigated the possible cause, “if you look at the source code within the app store, it looks significantly different from what’s in their GitHub. The gut reaction is that it’s something to do with their code.”

Using Advanced Encryption Standard (AES), Crypter is a simple concept. It encrypts and decrypts messages locally on the users’ computers, using an agreed-upon password between sender and receiver. As a sender types the message, it’s converted into ciphered text, sent to the receiver via Facebook’s servers, and then decrypted on the receiver’s end.

Mitchell, a student at Sussex University, cites Internet privacy – specifically, the “growing concern with laws” that allow private companies and governments to “snoop” on private messages – as a reason behind Crypter.

“Because of the issue Crypter solves, it leaves itself open to be useful in a multitude of ways,” Mitchell writes on the Crypter homepage. “In countries where governments can persecute and kill for inciting protest, having a tool like Crypter would be incredibly beneficial for the oppressed. They can now use social media to spread and share ideas. Having something akin to Crypter could have completely rewritten history in respect to events like the Arab Spring.” On the flip side, terrorist groups, such as the social media-savvy Islamic State, could also benefit from such a tool.

One of the “benefits” Crypter touts concerns advertising: Because messages are encrypted, Facebook wouldn’t be able to serve targeted ads to users. With advertising driving the social network’s profits, one could speculate that Crypter may have raised red flags, but Facebook tells us this isn’t the case at all. (Facebook, in fact, has a policy of keeping messages private and secured, so an app like Crypter would only be a good thing.)

The company hopes Crypter “can find a way to fix it, but it wasn’t anything that was done on our side. We’re not shy about it, if we had done something, we would have told them exactly why.”

Although the app no longer functions, it’s still available for download, to anyone who wants to help resurrect the app.

“I would love some help with this setback. You can find our GitHub on our website,” Mitchell says.